Copolymers of tetrahydrofuran (hereinafter referred to as “THF”), in this case polytetrahydrofuran (hereinafter referred to as “PTHF”); is a polymer with diol functionality that is used as an intermediate for the preparation of polyurethane, polyester and polyamide elastomers. Incorporation of PTHF into these polymers imparts softness and flexibility to these polymers.
PTHF is made from THF through cationic ring opening polymerization in the presence of a catalyst. Becker et al in U.S. Pat. No. 5,773,648 has disclosed that the catalyst used in the process for cationic ring opening polymerization are strong Lewis acids (boron trichloride, aluminium trichloride, iron trichloride and tin tetrachloride) and strong Bronsted acids (tetrafluoroboric acid, fluorosulfonic acid, perchloric acid and chlorosulfonic acid). Heterogeneous catalysts used in the process are zeolite, ammonium paratungstate supported on titanium dioxide, Nafion ion exchange resin, sulfate doped zirconium oxide and bleaching earth.
Additionally, it has been reported by Feng et al in Polymer Bulletin (1990) that copolymerization of THF with cyclic ethers such as ethylene oxide and propylene oxide was conducted to impart specific properties to the polymer such as lower crystallinity that will yield lower temperature flexibility to the polymer. The incorporation of cyclic ethers also makes the polymer more hydrophilic that is desired for specific application.
Currently, all the feedstock for the production of PTHF, namely THF, ethylene oxide and propylene oxide are originated from petroleum-based chemicals. However, due to rising cost of crude oil and environmental concerns, there are interests in producing PTHF with incorporated renewable content. To date, there is no report of PTHF made with copolymerizing THF with renewable cyclic ethers such as epoxidized natural oils. Therefore, it is an objective of this invention to polymerize THF with a renewable co-monomer, namely epoxidized natural oils. The most fundamental difference in method of producing copolymers (PTHF) disclosed in this invention is the use of epoxidized oil from natural sources (like palm oil) as the co-monomer in polymerization of THF.
The produced copolymers PTHF were then used as raw material for the production of polyurethane and polyurea.